Carbon Footprint between Steel-Reinforced Concrete and UHPC Beams

Abstract

Due to its superior mechanical and durability performance, ultrahigh performance concrete (UHPC) has gained increasing applications worldwide. While studies have suggested different strategies to design reinforced UHPC beams, their resulting structural behavior is not yet well understood, and their carbon footprint has not been given considerable attention. Based on nonlinear finite element simulations and cradle-to-gate life-cycle analyses, this study compares the performance of two steel-reinforced concrete beams to steel-reinforced UHPC (R/UHPC) beams with the same flexural load capacity but different design strategies. Results show that an R/UHPC beam of the same cross-section but lower reinforcing ratio of a conventional concrete beam could show 166% higher carbon emission and 64% less deformation capacity than a control steel-reinforced concrete beam. On the other hand, a well-designed R/UHPC beam can (1) maintain the carbon footprint; (2) reduce the section size and steel bar usage by 50% and 30%–53%, respectively; and (3) show equivalent or higher service-level stiffness and ultimate deformation capacity.